Synchro adjustment tool



May 19, 1964 w. s. DAVIS m SYNCHRO ADJUSTMENT TOOL Filed Dec. 27, 1960 w i Nu INVENTOR. WILLIAM S. DAVIS,III BY United States Patent 3,133,463 SYNCHRO ADJUSTMENT TOOL William S. Davis III, San Diego, Calili, assignor to The Ryan Aeronautical Co., San Diego, Calif. Filed Dec. 27, 1960, Ser. No. 78,506 4 Claims. (Cl. 81-65) The present invention relates generally to hand tools and more particularly to a synchro adjustment tool.

In various types of electronic apparatus such as stable platforms, gyroscope units, and combined accelerometergyroscope systems, to mention but a few examples, there are numerous synchronizing or repeating devices commonly referred to as synchros, which are normally of cylindrical form. In assembling or servicing such apparatus, it is necessary to adjust the synchros in their working positions, the adjustments usually being made by rotating the synchros about their axes and the rotation involved being a very small angular rotation, often on the order of a few minutes or even seconds of arc. In addition, the synchros are invariably situated in extremely confined spaces and must be handled carefully to avoid damage, the type of apparatus involved being in the category of precision instruments.

The primary object of this invention, therefore, is to provide a synchro adjustment tool which can be applied to a synchro in a confined space and locked positively to the synchro for accurate adjustment, the tool utilizing a thin, flexible strap which encircles the synchro and applies pressure evenly to avoid distortion or damage, the strap being the only portion of the tool in direct contact with the synchro.

Another object of this invention is to provide a synchro adjustment tool in which the flexible strap has a swivelling connection at one end and a quick release attachment at the other, for ease of application and handling.

Another object of this invention is to provide a synchro adjustment tool having a quick acting lock means for initially holding the tool in place on the synchro, while the flexible strap is carefully tightened to the required tension to turn the synchro.

A further object of this invention is to provide a synchro adjustment tool having a strap holding yoke which holds the flexible strap accurately in alignment on the synchro.

Finally, it is an object to provide a synchro adjustment tool of the aforementioned character which is simple and convenient to manufacture and use and which will give generally efficient and durable service.

With these and other objects definitely in view, this invention consists in the novel construction, combination and arrangement of elements and portions, as will be hereinafter fully described in the specification, particularly pointed out in the claims, and illustrated in the drawing which forms a material part of this disclosure, and in which:

FIGURE 1 is a side elevation view of the tool;

FIGURE 2 is a sectional view taken on the line 22 of FIGURE 1;

FIGURE 3 is a sectional view taken on the line 33 of FIGURE 1;

FIGURE 4 is an end elevation view as taken from the right end of FIGURE 1;

FIGURE 5 is a fragmentary sectional view similar to a portion of FIGURE 2, but showing the bolt extended and the strap disengaged; and

FIGURE 6 is a side elevation view of the bolt and strap connection.

Similar characters of reference indicate similar or identical elements and portions throughout the specification and throughout the views of the drawing.

The tool comprises cylindrical handle or barrel 10 hav- 3,133,463 Patented May 19, 1964 ing a smooth internal bore 12, one end of said barrel having a bifurcated yoke 14, the arms of which have smoothly curved inner faces 16 flaring outwardly from the end of said bore. In lateral dimension the Width of the yoke 14 is equal to the diameter of the barrel 10, so that a minimum of clearance is needed in the working area. Inside the barrel 10 is an axially slidable bolt 18, at the forward end of which is an extended lug 20. Straddling the lug 20 is a clevis 22 pivotally secured by a pin 24 and fixed by one end to said clevis is an elongated, flexible strap 26 of thin, flat strip material. The strap 26 is preferably of material which is reasonably soft, so as not to damage the casing of the synchro, yet has a certain amount of resiliency to facilitate its manipulation in confined spaces, aluminum alloy or similar material being suitable. On one side of the bolt 18, adjacent the forward end, is a recessed flat portion 28 and fixed in said bolt is a retaining pin 30 projecting radially from the flat portion, the end of said retaining pin having a minimum clearance from the wall of the bore 12, as in FIGURE 2. The free end of the strap 26 is provided with an opening 32 for engagement over the retaining pin 30 alongside the bolt.

Integral with the bolt 18 and extending axially from the rear end thereof is a threaded shaft 34, which is engaged in a clamp nut 36, said clamp nut having an elongated sleeve portion 38 extending inside the barrel 10 to allow for a considerable range of adjustment. The clamp nut 36 is externally knurled, as at 40, for manual operation and has a radially extending flange 42 which bears against the end of the barrel 10.

For quick locking of the bolt 18, the forward end of the barrel 10 has a longitudinal slot 44, through which a thumb screw 46 is inserted diametrically into said bolt, the barrel having a flattened portion 48 coextensive with said slot against which the head 50 of said thumb screw seats when tightened.

In use, the clamp nut 36 is backed off and the thumb screw 46 is loosened, allowing the bolt 18 to be extended from the barrel 10, as in FIGURE 5. When the retaining pin 30 is clear of the barrel 10, the strap 26 can be disengaged and the free end of the strap passed around the synchro to be adjusted. In some instances there may be only a few hundredths of an inch clearance between a synchro and its associated motor and the thin strap is threaded completely around the synchro and the end attached to the retaining pin 30. The bolt 18 is then quickly retracted and locked in place by means of the thumb screw 46, to hold the strap 26 initially in place. The yoke 14 straddles a portion of the synchro, indicated in broken line at 52 in FIGURE 2, facilitating accurate positioning and alignment of the strap. It should be noted that the surface of the synchro 52 is contacted only by the strap 26, the area of the synchro straddled by the yoke 14 being protected by the portions of the strap disposed across the curved inner faces 16. When the tool is correctly positioned with sufficient clearance for the required movement, the strap 26 is tightened by means of the clamp nut 36 to grip the synchro just tightly enough to permit rotation as needed, the barrel 10 serving as a handle or lever. When adjustment is completed, the clamp nut and thumb screw are loosened and the bolt extended to release the strap.

While the tool is primarily designed for the precise operation of adjusting synchros and the like, it will be evident that the arrangement is adaptable to other uses requiring a strap type wrench. Conversely, conventional types of strap wrenches are not readily adaptable to synchro adjustment since they are not normally designed for use in very confined quarters and often have gripping teeth or lever locking devices which would damage the synchros. The synchro adjustment tool fulfills 3 a specific purpose effectively due to its particular design, the quick acting locking being an especially important feature.

The operation of this invention will be clearly comprehended from a consideration of the foregoing description of the mechanical details thereof, taken in connection with the drawing and the above recited objects. It will be obvious that all said objects are amply achieved by this invention.

It is understood that minor variation from the form of the invention disclosed herein may be made without departure from the spirit and scope of the invention, and that'the specification and drawing are to be considered as merely illustrative rather than limiting.

I claim:

1. A synchro adjustment tool, comprising: an elon gated tubular barrel; a bolt longitudinally slidably mounted in said barrel; a thin, flexible strap having one end attached to one end of said bolt; the other end of said strap being detachably secured to said bolt; and means engaging said bolt for retracting said bolt and the ends of said strap into said barrel with the center portion of said strap protruding from said barrel to form a loop having a smooth, inner surface disposed to grip a cylindrical body, said surface being the only portion of said tool to grip said body; said retracting means comprising a longitudinal slot in said tubular barrel, and a protrusion engaged with said bolt and extending outwardly through said slot, said protrusion having adjustable means for locking said bolt.

2. A synchro adjustment tool, comprising: an elongated tubular barrel having a longitudinal slot and a bifurcated yoke at one end of said barrel, said yoke having smooth inner faces flaring outwardly from said barrel; a bolt longitudinally slidably mounted in said barrel; a thin, flexible strap having one end attached to one end of said bolt; the other end of said strap being detachably secured adjacent said end of said bolt to hold the strap in a loop for encircling a synchro; and retracting means engaging said bolt to retain the bolt at any position in said barrel, said means comprising a thumb screw threadedly engaged with said bolt and extending through said slot, the head of said thumb screw being frictionably engageable with the periphery of said slot.

3. A synchro adjustment tool, comprising: an elongated tubular barrel having a longitudinal slot and a bifurcated yoke at one end of said barrel, said yoke having smooth inner faces flaring outwardly from said barrel; a bolt longitudinally slidably mounted in said barrel; a thin, flexible strap having one end attached to one end of said bolt; the other end of said strap being detachably secured to said bolt to hold the strap in a loop for encircling a synchro; loop tightening means engaging said bolt and extending outwardly through said slot to retract the bolt and said ends of said strap into said barrel; and additional loop-tightening means for further retracting said bolt into said barrel.

4. A synchro adjustment tool, comprising: an elongated tubular barrel having a longitudinal slot and a bifurcated yoke at one end of said barrel, said yoke having smooth inner faces flaring outwardly from said barrel; a bolt longitudinally slidably mounted in said barrel, said bolt having an elongated threaded portion at one end; a lug integral with the other end of said bolt; a thin flexible strap pivotally attached at one end to said lug; a retaining pin fixed in said bolt adjacent said lug; the other end of said strap being engageable with said retaining pin to hold the strap in a loop for encircling a synchro; means, comprising a thumb screw threadedly engaged in said bolt and extending through said slot, for quickly retracting said bolt into said barrel with said loop protruding through said bifurcated yoke; means, comprising the head of said thumb screw and the periphery of said slot, for locking said bolt in the retracted position; and means, comprising a clamp nut engaging said threaded portion of said bolt, for further retracting said bolt into said barrel and tightening said loop around said synchro.

References Cited in the file of this patent UNITED STATES PATENTS 1,015,667 Caryl Jan. 23, 1912 1,130,863 Wallace Mar. 9, 1915 1,638,918 Clark Aug. 16, 1927 2,498,934 Webb Feb. 28, 1950 2,706,423 Rose Apr. 19, 1955 2,889,726 Strabeck June 9, 1959 3,023,649 Wallace Mar. 6, 1962 

1. A SYNCHRO ADJUSTMENT TOOL, COMPRISING: AN ELONGATED TUBULAR BARREL; A BOLT LONGITUDINALLY SLIDABLY MOUNTED IN SAID BARREL; A THIN, FLEXIBLE STRAP HAVING ONE END ATTACHED TO ONE END OF SAID BOLT; THE OTHER END OF SAID STRAP BEING DETACHABLY SECURED TO SAID BOLT; AND MEANS ENGAGING SAID BOLT FOR RETRACTING SAID BOLT AND THE ENDS OF SAID STRAP INTO SAID BARREL WITH THE CENTER PORTION OF SAID STRAP PROTRUDING FROM SAID BARREL TO FORM A LOOP HAVING A SMOOTH, INNER SURFACE DISPOSED TO GRIP A CYLINDRICAL BODY, SAID SURFACE BEING THE ONLY PORTION OF SAID TOOL TO GRIP SAID BODY; SAID RETRACTING MEANS COMPRISING A LONGITUDINAL SLOT IN SAID TUBULAR BARREL, AND A PROTRUSION ENGAGED WITH SAID BOLT AND EXTENDING OUTWARDLY THROUGH SAID SLOT, SAID PROTRUSION HAVING ADJUSTABLE MEANS FOR LOCKING SAID BOLT. 